Reproducer



M. JONES. REPRODUCER- APPLICATION FILED JUNE 19, I917- lAl 5,36 1Patented May 9, 1922} MARTIN JONES, 0F PHILADELPHIA. PENNSYLVANIA,ASSIGNOR O'F' ONE-HALF TO' JOSEPH S. MAOLAUGHLIN, OF PHILADELPHIA,PENNSYLVANIA.

BEPRODUCER.

Specification of Letters Patent.

Patented May 9, 1922.

Application filed June 19, "1917. Serial No. 175,628.

To all whom it may concern:

Be it known that I. MARTIN JoNns, a citizen of the United States.residing in Philadelphia, Pennsylvania, have invented a Reproducer, ofwhich the following is a specification. I

One object of my invention is to' provide a sound box or reproducer fortalking machines which shall be capable of so affecting the sound wavesas to produce the required volume of sound without being as heavy as isat present the practice. By reason of the resulting lightening of thereproducer structure there is a reduction of the pressure upon therecord and a consequent increase in the useful life of the latter.

A further object of the invention is to so construct a sound box that itshall be capable of giving a more perfect and clearer reproduction of agiven .record than is now possible by the use of sound boxes of asimilar p I The invention also contemplates a novel arrangement and formof intermediate diaphragm whereby the above noted desirable results areobtained and also a construction whereby vibration of the body of thebox is prevented or damped, as are also certain objectionable metallicnoises commonly produced when records of a certain class are played.-

These objects and other advantageous ends I secure as hereinafter setforth, reference being had to the accompanying drawings, in which,

Fig. 1 is a plan of a sound box or reproducer constructed according tomy invention;

Fig. 2 is a vertical section on the line 2-2, Fig; 1; and

Fig. 3 is a plan of the auxiliary diaphragm forming part of myinvention. p In the above drawings, 1 represents the body of a sound boxwhich consists of a flat disk or plate having a tubular boss 2projecting from the center of one of its facesfor attachment to the tonearm or horn of a talking machine. The opposite fiace of the body 1 hasan outwardly projecting flange 3 whereby there is formed a shallowcylindrical cavity whose circular bottom has cemented or otherwiseclosely held to it a thin, annular sheet 4: of dampening material suchas hard or soft rubber, asbestos, gutta. percha, or the like.

Parallel with but spaced away from this lining by a rubber gasket orwasher .5 within the cavityof the body. is an auxiliary diaphragm 6,preferably consisting of a circular body ofvulcanized fibre orequivalent material, of less diameter than the cavity of the body buthaving at opposite points projections 7 which rest upon the washer 0rgasket 5. A second gasket or washer 8 rests upon these projectingportions 7 and upon the intermediate portions of the washer 5 and thishas the customary mica diaphragm 9 held to it by a metal ring 10threaded into the cavity of the diaphragm ;there being a third washer orgasket 11 interposed between this ring and the mica disk.

A stylus lever 12 of any desired construction has one end cemented tothe center of the mica diaphragm and if necessary the auxiliarydiaphragm 6 is centrally perforated to avoid contact with the adjacentprojecting portion of its end. Said stylus lever extends radiallyoutward from the center of the face ofthe sound box and has a transverseportion 13 engaged by a pair of trunnion screws 14 which pass looselythrough a pair of lugs 15 respectively projecting up from the outer edgeof the flange 3. Each trunnion screw however, has threaded upon it apair of nuts 16 which cooperate with the lug 15 to immovably hold saidtrunnion inany adjusted position. The outer portion 17 of the styluslever is provided with an axial passage or recess for the reception of aneedle and has a clamping screw 18 whereby said needle may be rigidlyheld in place.

By repeated tests I have found that a sound box f the above describedconstruction possesses advantageous features totally lacking in similardevices at present in use, it appearing that the intermediate diaphragm6 has such an effect upon the sound waves so that the most perfectreproduction of a record is obtained. As shown in the drawings, thediameter of the body of this auxiliary diaphragm is such that there isan annular opening between the spaces in front and at the back ofit,which-opening is of course bridged by the supporting projections 7.

' By the use of the rubber or other dampen. ing lining the blare ormetallic noise fre quently heard in reproducing certain records areeliminated, this apparently being due to the fact that th Vibration ofthe body of the sound box is in a large measure prevented or damped.Moreover by the construction employed no metallic part of the sound boxis exposed to the direct action of the sound Waves produced.

By providing lugs 15 through Which the trunnions pass loosely, but towhich they are rigidly clamped by their respective pairs of jam nuts, Ihave found that the loosening of the trunnions' and their gradualdisengagement from the stylus lever has been effectually prevented.

I claim v The combination in a sound box of a body having a cylindricalcavity closed at one end'; a main diaphragm mounted across said cavity;a stylus lever attached to said diaphragm; an auxiliary diaphragm in theform of a relatively thin light disc of vulgcanized fibre less indiameter than the cavity MARTiN JONES.

